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However, that could change in future. Research published today in the journal Matter & Light describes the efforts of Chinese engineers to build a system that can charge drones using laser beams. It’s based on a solar cell design, and can be attached to the underside of a drone’s wings to harvest energy from a laser beam fired from the ground.
“Imagine a future where drones inspecting forests, monitoring disasters or delivering packages no longer need to land frequently to replace batteries,” says senior author Jianhua Han of the Civil Aviation University of China. “As drones take on longer missions, battery life has become one of the biggest barriers.”
The technology used a perovskite laser cell-thermoelectric tandem device, a type of solar cell optimised for lasers rather than sunlight. There are two layers: the perovskite layer converts laser energy into electricity, and a thermoelectric layer captures energy that would otherwise be lost to heat.
“When we tested the device under a high-power laser, the thermal camera showed temperatures of 80 to 90 degrees Celsius,” says Han. “That was much higher than we expected and made us realise that heat build-up was a far more serious problem than we had imagined.”
To keep the device from getting too hot, the researchers embedded specialised nanocrystals to act as a thermal barrier, slowing the flow of heat and helping the device maintain its performance during prolonged laser exposure. The system converted 38.49% of the incoming energy into electricity.
As a proof of concept, the team also integrated the device beneath the wing of a stationary drone model and carved out air channels through the wing. Shining a green laser on the device successfully powered the model’s propellor blade. Moreover, the airflow further cooled the cold side of the thermoelectric layer, boosting the device’s overall performance.
“Previous studies largely focused on the materials or the device itself,” says Han. “We wanted to think beyond the laboratory, to how the system could actually be integrated into an aircraft, cooled during operation and made compatible with flight. It isn’t just a materials science problem; it’s an engineering one.”
The next step will be to test the technology on board a lightweight drone to prove it can work outdoors. After that, engineers will need to figure out how to accurately track a drone with a laser beam, and how to do so safely. “Our work demonstrates the possibility of ‘refuelling aircraft with light,’” says Han. “Going from one to 100 will require solving many engineering challenges, but we hope this provides a starting point for future development.”
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